1. Field of the Invention
The present invention relates generally to disk drives, and more particularly to a disk drive having electrical traces formed upon a disk drive housing.
2. Description of the Prior Art
The typical hard disk drive includes a disk drive base, and a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to the disk drive base. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA) that includes at least one transducer head, typically several, for reading and writing data to and from the disk. As discussed further below, the printed circuit board includes functional portions of which may be characterized as spindle motor drive circuitry, actuator drive circuitry, and read channel circuitry.
The head stack assembly includes an actuator assembly, at least one head gimbal assembly, and a flex circuit cable assembly. A conventional “rotary” or “swing-type” actuator assembly typically comprises an actuator body that rotates on a pivot assembly between limited positions, a coil portion that extends from one side of the actuator body to interact with one or more permanent magnets to form a voice coil motor, and one or more actuator arms which extend from an opposite side of the actuator body. The actuator assembly includes the actuator body which has a bore and a pivot bearing cartridge engaged within the bore. A head gimbal assembly includes at least one transducer head, sometimes two, which is distally attached to each of the actuator arms.
The flex circuit cable assembly includes a flex circuit cable which is attached to the actuator assembly and electrically connects the various electrical components onboard the head stack assembly with a relatively minimal impact upon its pivoting movement. The actuator drive circuitry is configured to generate servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the actuator drive circuitry. In so doing, the attached heads are moved relative to tracks disposed upon the disk. As such, the flex circuit cable houses electrical connections between actuator drive circuitry and the coil portion of the actuator assembly. Further, the read channel circuitry is configured to receive data signal from the heads. As such, the flex circuit cable further houses the electrical connections between the read channel circuitry and the heads.
The spindle motor includes a hub that is rotatably attached to the disk drive base. The hub has an outer flange that supports one of the disks. Additional disks may be stacked and separated with spacers. The spindle motor further includes an annular magnet and a spindle motor stator. Where space efficiency is of vital concern, the magnet is typically attached about the lowermost portion of the hub below the flange. The magnet consists of a predetermined number of N and S poles that are disposed alternately circumferentially about the magnet. The spindle motor stator includes an outer rim that is attached to the disk drive base and a plurality of internally facing stator teeth. The stator teeth are equally spaced and extend from the stator rim. The spindle motor stator is sized to fit about the hub and in particular the magnet. Each stator tooth includes windings which selectively conduct current to create a magnetic field that interacts with the various poles of the magnet. Such interaction results in forces applied to the hub which tend to rotate the hub. The spindle motor drive circuitry is configured to generate electrical signals to the stator, and in particular the windings thereof, for controlling the movement of the spindle motor.
A topic of concern is the desire to reduce the overall disk drive size. Such disk drives may have a variety of applications in any number of host electronic devices, such as hand held or portable devices such as computer laptops, cellular telephones, personal digital assistants (PDA), digital cameras, etc. In this regard, a disk drive may be of an internal nature or externally connectable such as in a socket, port or other interface of the associated host electronic unit. The exterior size and shape of the disk drive is often referred to as a “form factor”. Reduction of such disk drive form factor has proven challenging. This is because the mere reduction of the size of the various disk drive components may result in such components being unable to conform to required specifications and standard form factors for such components, and may result in installation or assembly difficulties. In this regard, one particular area of focus is the electrical connections between the various electrical components of the disk drive. Accordingly, there is a need in the art for an improved arrangement for the electrical connections between various disk drive electrical components in comparison to the prior art.